On Numerical Solutions in Open String Field Theory

Abstract

We have constructed numerical solutions in the Siegel gauge in the theory around the Takahashi-Tanimoto solution (TT solution) with one real parameter a ( ≥− 1/2). We have used the level truncation approximation in the su(1, 1) singlet basis. In particular, we have performed numerical calculations up to level (26, 78) in the case a = 0, which corresponds to the conventional equation of motion, and a = −1/2, which gives a nontrivial solution. For these obtained solutions, we have evaluated gauge invariants, potential height and gauge invariant overlap, and the results provide further evidence of the previous expectation that the TT solution with a = −1/2 gives the nonperturvative vacuum, where a D-brane vanishes, while that with a> −1/2 is pure gauge.